Snap-action mechanism



Jan. 2, 1951 ROCKWELL 2,536,141

SNAP ACTION MECHANISM Original Filed Sept. 19, 1942 2 Sheets-Sheet 1 Q-km lNVENTOR Edward A. Rock-we'll \0 m ATTORNEY 2 Sheets-Sheet 2 OriginalFiled Sept. 19, 1942 v8 NB 9 QQMA W Mm ATTOR N EY INVENTOR Ecwmd J1.liockwe [1 Patented Jan. 2, 1951 UNITED STATES PATENT OFFICE 2,536,141SNAP-ACTION MECHANISM Edward A. Rockwell, Cleveland, Ohio Originalapplication September 19, 1942, Serial No. 459,045. Divided and thisapplication Jan.- nary 24, 1945, Serial No. 574,32

Claims. 1

My invention relates particularly to a snapaction mechanism adapted tobe used Within a desired device to be moved quickly from one position toanother.

The present application is a division of my copending application uponUnloader Valve, Serial No. 459,045, filed September 19, 1942, Patent No.2,372,016, granted March 20, 1945.

The object of my invention is to provide a snap-action mechanism adaptedto shift quickly any device desired to be moved thereby. Another objectis to provide a mechanism of this character which is capable of beingadjusted so as to alter the point at which the snap-action comes intooperation for moving the said device. Another object is to provide anapparatus of this character having a plunger and a piston which issubjected to a hydraulic pressure determining the point at which thesnap-action mechanism is actuated. Another object is to provide acompact apparatus of this character in which the element which controlsthe opera-- tion of the snap-action device is operated by means of ahelical spring extending around the plunger which carries the saidelement. Still another object is to provide a ball detent for the saidelement and which preferably is provided on a set of balls having acircularly-arranged helical spring in a circular recess for controllingthe said balls.

While my invention is capable of being carried out in many differentWays, for the purpose of illustration I have shown only one form of myinvention in the accompanying drawings, in which- Fig. 1 is a verticalsection of a snap-action mechanism made in accordance with my invention,and

Fig. 2 is a diagrammatic representation of a pump circuit in which thesame is adapted to be used, as applied, for example, to the operation ofa hydraulic jack, such, for instance, as the jack used in operating theretracting undercarriage for the wheels of an airplane.

In the drawings, for supplying the hydraulic pressure I have shown apump l of any desired character, but as, for example, a continuouslyoperating gear pump which may be driven from the engine of an airplanein any desired Way. The pump 1 is connected by a pipe 2 to an inlet port3 of a valve casing 4 which may be supported on the airplane in anydesired manner. The port 3 leads to a valve chamber 5 which is closed atone end by a screw ring 6 having an opening 7 which is sealed by anannular rubber seal 2 8 held in place a screw plug Q provided with asquared head it. A screw ring H is carried over the outside of the screwring 6 and the plug 9. In the interior of the plug 9 there is a flutedrecess 22' for receiving an end I3, having a fluted end it, of anelement such as a shiftable release valve operating rod !5 for adjustingspring tensions. Supported around the plug 9 there is a helical springit, one end or which rests against the screw ring 6 and the other end ofwhich extends into an annular release valve H where it rests against ashoulder l3 therein. The said release valve H has thereon a sleeve 19having an annular rubber seal 21') arranged to slide within the screwring 6. At the left-hand end of said valve there is a conical valveelement 25 which cooperates with an annular insertable valve seat 22supported within a lateral passageway 23 in the valve cas- The sleeve isis an annular balanced valve member which has the effect of balancingthe large valve H so that it can be opened by small operating forces.Accordingly, the light spring It can be used, which is of onlysuflicient strength to return the valve H to its seat. The saidpassageway 23 leads to an exhaust port is which communicates with areturn pipe 25. The said spring it normally keeps the conical valvemember 2i on its seat 22, and parts are associated with the valveoperating rod l5 for unseating the said valve member 25 when thepressure delivered by the unloader valve mechanism reaches a certaindegree; For this purpose, on the valve operating rod I5 there are,tightly secured in recesses, annular stops or split rings 25 and 2?.Adjacent to the split ring 26 there is a spring supporting sleeve 28having a flange 29 to support a helical spring 33, acting as a yieldingspring pressure accumulating means in one direction. The flange 29 restsagainst a split ring 35 located in a recess in a spring housing 32. Thespring housing 32 has a restricted annular end 33 which is slidablycarried upon the valve operating rod l5. On the outside of the springhousing 32 there is an annular flange 34 or detent which acts as aninterrupted surface cooperating with a circular set or series of balls35 located around the housing 32, in recesses 35a, and pressed towardsthe same by an annular helical spring 36 forming a completeuninterrupted circle within an annular recess}? which is contained in anauxiliary valve casing 38 provided with a flange 39 for securing thesame to the Valve casing 4 by means of screws 40, a gasket 4| being 3provided to make a tight joint. In the recess 3? there is located aportion of the valve casing t forming a spring retaining ring 42 againstwhich one end of a strong helical spring 53 rests, the said spring 43being located in a transverse cylindrical chamber 44 in the auxiliarycasing 38, said chamber 44 and passageway 23 being a discharge chamber.The other end of the helical spring 43 is supported by a disk at on thevalve operating rod It, on which it is held in place by an ad ustingmeans such as a screw-threaded non-rotatable sleeve ii; havinglongitudinal grooves H, in one of which a key pin so, passing throughthe auxiliary casing 38, is adapted to slide to permit ad ustment oi thetension of the spring 03. This ad ustrnent of the disk 45 is limitedowing to the fact that disc movement stops against the left face or thesplit ring 2?. On the right-hand face of the split ring 27 there is aspring sleeve 48 having a flange b which rests against a split ring 5!in a recess within a spring housing 52. A helical spring 53 is locatedaround the rod it between the spring sleeve &9 and the spring housing52, acting as a yielding spring pressure accumulating means in the otherdirection. The lei't-hand end 54 of the Valve operating rod I5 isprovided with a stop extension 53a and a number of annular oil recesses55 for sealing the same, and said end o l is adapted to act as a pistonor plunger so as to be moved by the oil pressure in a chamber 56 whichhas a connection with a passageway 51'] in said auxiliary casing 38communicating with a passageway 58 in the valve casing ei. The hydraulicpressure in said passageway 5'1 operates in opposition to said spring43. A tight connection is made between the passageways 5i and 58 by atube 59 having around the same a rubber ring 66 located at the jointbetween the casings t and 38. The said passageway 58, at the righthandend thereof, leads to a vertical chamber iii in the casing 4, which isclosed by a screw plug 62 having a projection 63 thereon to act as aguide for a helical spring 6 1, the lower end of which rests upon thetop of a check-valve t5 cooperating with an annular valve seat 66carried in said chamber Bl. In order to pro-- vide means for applyingthe hydraulic pressure so as to supply the needed force for workperformance, at the side of the chamber 61 there is an outlet port 63which leads to a pipe 69 which may act as or be an accumulator forconveying the pressure liquid to a hand valve 76 for controlling thesupply of the pressure liquid to the respective ends of a cylinder H ofa jack, which may be used, for example, for controlling the extendingand retracting gear or one or more of the wheels of an airplane. Whileany type of valve iii might be used for this purpose, as showndiagrammatically, it is comprised of two crossed passageways l2 and 13,one of which is adapted to connect the pipe 69 to the cylinder H by apipe 74, while the other passageway connects the other end of a cylinderll, by a pipe '15, to a pipe l8 leading to the pipe 15, and thence by apipe H to a filter i8 and a pipe i9 leading to a reservoir Bi! and fromthe said reservoir 80, by a pipe 8|, to the intake of the pump I. Inother words, the hand valve i8 is so arranged that when it supplies thepressure liquid to either end of the cylinder H, the other end thereofmay be connected to the return pipe to the reservoir, although it is tobe understood that any other known type of valve mechanism can be usedfor the supply and discharge of the pressure liquid from the jack. Itwill, of course, be understood, also, that the cylinder H of the jackmay have a bracket 82 for its attachment to the airplane and a pistonrod 83, which is moved by a piston 88, for moving the particular wheelor wheels to which it may be attached.

In the operation of my invention, assuming that the airplane engine isbeing operated, the pump I will be driven accordingly and liquidtherefrom is available to be supplied by the pipe 2 through thecheck-valve 65 to the pipe 69 and thence to either end of the extendingand retracting mechanism for the airplane wheels operated by thecylinder H of the jack provided for the same. It will, of course, beunderstood that there may be one such jack with its manual operatingvalve provided for operating each particular wheel of the airplane. Whenthe pressure of the liquid which is thus supplied through the pipe 69reaches any desired given maximum, this pressure, which is conveyed alsothrough the passageway 51, will move the piston end 5% in opposition tothe spring $3. This movement will continue until it reaches a positioncompressing the spring 53, until finally the lateral pressure exerted bythe annular flange on the balls 35 is suflicient to overcome thepressure exerted on the balls 35 by the annular helical spring 36,whereupon the flange 35 will be moved suddenly and quickly past theballs 35 to the right side of said balls. This will bring the end of thespring housing 32 against the valve I! suddenly, so as to open the samewith a snap action, thus releasing the pressure liquid to be returned bythe pipe 25 to the reservoir 89 and back to the pump I until such timeas the pressure within the pipe 63 is lowered sufliciently to close thevalve ll. However, as the pressure is lowered, and before said valve llbecomes closed, the valve operating rod 55 will move to the left, whilethe spring :83 is expanding, resulting in compressing the spring 33until such time that the force exerted by the flange 3d towards the leftis sumcient to overcome the force of the annular helical spring 38,whereupon, under the influence of the spring 43, the flange 34 willsuddenly move to the left side of the balls 35, thus closing the valveI! suddenly and effectively with a snap action. Thus, the unloader valvemechanism will continue to operate in the manner described above tomaintain the given pressure being supplied through the pipe 69, and in amost effective manner, inasmuch as the valve I? will always be movedsuddenly and definitely in a minimum time interval to immediately changeany abnormal condition of pressure in the pipe 69, thus maintaining itsubstantially constant at all times.

While I have described my invention above in detail, I wish it to beunderstood that many changes may be made therein without departing fromthe spirit of the same.

I claim:

1. A snap-action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent restraining the movement of the element having an operativeconnection to said means for applying force, a spring urging the detentinto operative control of the element, yielding spring-pressureaccumulating means having an operative connection to said of twoopposite directions by the accumulated spring pressure according to therelative position of said element, said yielding means having aconnection to said means for applying force for forcing the element inone direction, a spring means for bringing about the movement of saidelement in the other direction and a member screw=threaded to saidelement" for adjusting the point at which said last-i-mentioned springmeans acts to move the element.

2 A snap action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent restraining the movement of the element having an operativeconnection to said means for applying force, a spring urging the detentinto operative control of the element, yielding spring-pressureaccumulating means having an operative connection to said elementadapted to urge the ele ment in each of two opposite directions by theaccumulated spring pressure according to the relative position of saide1ement,said yielding means having a connection to said means forapplying force for forcing the element in one direction, a spring meansfor bringing about the moverrent of said element in the other directionand means for adjusting the point at which said last-mentioned springmeans acts to move the element, comprising an adjusting rod extending soas to be accessible to the outside of the mechanism.

3. A snap-action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent restraining the movement of the element having an operativeconnection to said means for applying force, a spring urging the detentinto operative control of the element, yielding spring-pressureaccumulating means having an operative connection to said element andhaving a plunger subject to said pressure, adapted to urge the elementin each of two opposite directions by the accumulated spring pressureaccording to the relative position of said element, said yielding meanshaving a connection to said means for applying force for forcing theelement in one direction, a spring means for bringing about the movementof said element in the other direction and a member screw-threaded tosaid element for adjusting the point at which said last-mentioned springmeans acts to move the element,

4. A snap-action mechanism comprising, means for applying a force, anelement having operative connection to said means for applying force, adetent restraining the movement of the element having an operativeconnection to said means for applying force, a spring urging the detentinto operative control of the element, yielding spring-pressureaccumulating means having an operative connection to said element andhaving a plunger subject to said pressure,

to urge the element in each of two opposite directions by theaccumulated spring pressure according to the relative position of saidelement, said yielding means having a connection to said means forapplying force for forcing the element in one direction, a spring meansfor bringing about the movement of said element in the other directionand means for adjusting the point at which said last-mentioned springmeans acts to move the element, comprising an adjust- .ing rod extendingso asto be accessible to the outside of the mechanism.

5. A snap action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent comprising a circular set of balls restraining the movement ofthe element having an operative connection to said means for applyingforce, a spring urging the detent into operative control of the element,yielding springpressure accumulating means located co-axially with saidelement and having an operative connection. to said element adapted tourge the element in each of two opposite directions by the accumulatedspring pressure according to the relative position of said element, saidyielding means having a connection to said means for applying force forforcing the element in one direction and a spring for forcing saidelement in the other direction.

6. A snap-action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent comprising a circular set of balls restraining the movement ofthe element having an operative connection to said means for applyingforce, a spring urging the detent into operative control of the element,yielding spring pressure accumulating means located co-axially with saidelement and having an operative cons nection to said element and havinga piunger subject to said pressure, adapted to urge the element in eachof two opposite directions by the accumulated spring pressure accordingto the relative position of said element, said yielding means having aconnection to said means for applying force for forcing the element inone direction and a spring for forcing said element in the otherdirection.

'Z. A snap-action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent restraining the movement of the element having an operativeconnection to said means for applying force, means urging the detentinto operative control of the element, yielding means having anoperative connection to said element adapted to urge the element in eachof two different directions according to the relative position of saidelement, said yielding means having a connection to said means forapplying force for forcing the element in one direction, a spring meansfor bringing about the movement of said element in the other directionand a member screw-threaded to said element for adjusting the point atwhich the element is moved.

-8. A snap-action mechanism comprising, means for applying a force, anelement having anoperative connection to said means for applying force,a detent restraining the movement of the element having an operativeconnection to said means for applying force, means urging the detentinto operative control of the element, yielding means having anoperative connection to said element adapted to urge the element in eachof two different directions according to the relative position of saidelement, said yielding means having a connection to said means forapplying force for forcing the element in one direction, a spring meansfor bringing about the movement of said element in the other directionand a member screw-threaded to said element for adjusting the point atwhich said last-mentioned spring means acts to move the element.

9. A snap-action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent restraining the movement of the element having an operativeconnection to said means for applying force, means urging the detentinto operative control of the element, yielding means having anoperative connection to said element adapted to urge the element in eachof two different directions according to the relative position of saidelement, said yielding means having a connection to said means forapplying force for forcing the element in one direction, a spring meansfor bringing about the movement of said element in the other directionand means for adjusting the point at which the element is moved,comprising an adjusting rod concentric with the spring means.

10. A snap-action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent restraining the movement of the element having an operativeconnection to said means for applying force, means urging the detentinto operative control of the element, yielding means having anoperative connection to said element adapted to urge the element in eachof two different directions according to the relative position of saidelement, said yielding means having a connection to said means forapplying force for forcing the element in one direction, a spring meansfor bringing about the movement of said element in the other directionand means for adjusting the point at which said last-mentioned springmeans acts to move the element, comprising an adjusting rod concentricwith the spring means.

11. A snap-action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent restraining the movement of the element having an operativeconnection to said means for applying force, means urging the detentinto operative control of the element, yielding means having anoperative connection to said element adapted to urge the element in eachof two diiferent directions according to the relative position of saidelement, said yielding means having a connection to said means forapplying force for forcing the element in one direction, a spring meansfor bringing about the movement of said element in the other directionand means for adjusting the point at which the element is moved,comprising an adjusting rod and a non-rotatable sleeve associatedtherewith. v

12. A snap-action mechanism comprising, means for applying a force, anelement having an operative connection to said means for apply ingforce, a detent restraining the movement of the element having anoperative connection to said means for applying force, means urging thedetent into operative control of the element, yielding means having anoperative connection to said element adapted to urge the element in eachof two different directions according to the relative position of saidelement, said yielding means having a connection to said means forapplying force for forcing the element in one direction, a spring meansfor bringing about the movement of said element in the other directionand means for adjusting the point at which said last-mentioned springmeans acts to move the element, comprising an adjustng rod and anonrotatable sleeve associated therewith.

13. A snap-action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent restraining the movement of the element having an operativeconnection to said means for applying force, means urging the detentinto operative control of the element, yielding means having anoperative connection to said element adapted to urge the element in eachof two difierent directions according to the relative position of saidelement, said yielding means having a connection to said means forapplying force for forcing the element in one direction, a spring meansfor bringing about the movement of said element in the other directionand means for adjusting the point at which the element is moved,comprising an adjusting rod and a screw-threaded nut having a relativelongitudinal movement with regard to said rod.

14. A snap-action mechanism comprising, means for applying a force, anelement having an operative connection to said means for applying force,a detent restraining the movement of the element having an operativeconnection to said means for applying force, means urging the detentinto operative control of the element, yielding means having anoperative connection to said element adapted to urge the element in eachof two different directions according to the relative position of saidelement, said yielding means having a connection to said means forapplying force for forcing the element in one direction, a spring meansfor bringing about the movement of said element in the other directionand means for adjusting the point at which said last-mentioned springmeans acts to move the element, comprising an adjustable rod and ascrew-threaded nut having a relative longitudinal movement with regardto said rod.

15. A snap-action mechanism comprising, means for applying a force, ashiftable rod having an operative connection to said mean for applyingforce, a detent restraining the movement of the rod having an operativeconnection to said means forapplying force, means urging the detent intooperative control of the rod, yielding spring means having an operativeconnection to said rod adapted to urge the rod in each of two oppositedirections according to the relative position of said rod, said yieldingspring means having a connection to said means for applying force forforcing the rod in one direction, a spring means for bringing about themovement of said rod in the other direction and a sleeve screwthreadedto the rod for adjusting the point at which said last mentioned springmeans acts to move the rod after the accumulation of spring pressure bythe yielding spring means.

EDWARD A. ROCKWELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PA'IENTS Newell Jan. 18, 1944

